A tonne of treesitter grammars

They wrote their own graphics renderering library for starters, that's bundled into the editor when compiled.

https://www.gpui.rs/

Every Unity game ships with three UI frameworks (IMGUI, UGUI, UI Elements) built-in, in addition to everything else the game engine supports, and the engine is only about 50 MB.

Is that really necessary for an ide? Seems like a ton of added complexity for little to no trade off or even a downside considering...

Yes. Zed is snappy in a way that makes my copy of Sublime Text 3 feel slow. Compared to VSC it feels like going from a video game at 40 FPS with 2-3 frames of input lag to 120 FPS.

You can read about it here:

https://zed.dev/blog/videogame

A renderer/rendering library for something as simple as a text editor is not (or is not supposed to be) a lot of code and should not take up a large amount of space in a binary. Odds are good it's the embedded Treesitter grammars and other things that Zed uses that takes up space.

It is Rust software, so there is probably a good 50-90% waste when it comes to just raw needed vs. actual lines of code in there, but there is no way anyone makes a renderer so overcomplicated that it takes up a meaningful part of the 500 MB or so Zed takes up on Windows.